use net8 assistant/net8 config assistant will walk you thru service name setup. You don't need to have 2 tnsnames if your client/server is on single machine.

you can test your connection as part of service name set up if your database is up and running.

you need to have Pro*C option to test c++ program. Oracle 8i version has that option in programmer options installation. Its not part of server setup in unix. not sure about NT. You have demo programs to test your Pro*C options. Go thru the documentation it will walk you thru...